.\" **************************************************************************
.\" *                                  _   _ ____  _
.\" *  Project                     ___| | | |  _ \| |
.\" *                             / __| | | | |_) | |
.\" *                            | (__| |_| |  _ <| |___
.\" *                             \___|\___/|_| \_\_____|
.\" *
.\" * Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
.\" *
.\" * This software is licensed as described in the file COPYING, which
.\" * you should have received as part of this distribution. The terms
.\" * are also available at https://curl.se/docs/copyright.html.
.\" *
.\" * You may opt to use, copy, modify, merge, publish, distribute and/or sell
.\" * copies of the Software, and permit persons to whom the Software is
.\" * furnished to do so, under the terms of the COPYING file.
.\" *
.\" * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
.\" * KIND, either express or implied.
.\" *
.\" * SPDX-License-Identifier: curl
.\" *
.\" **************************************************************************
.\"
.TH CURLOPT_STREAM_WEIGHT 3 "13 Sep 2015" libcurl libcurl
.SH NAME
CURLOPT_STREAM_WEIGHT \- numerical stream weight
.SH SYNOPSIS
.nf
#include <curl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_STREAM_WEIGHT, long weight);
.fi
.SH DESCRIPTION
Set the long \fIweight\fP to a number between 1 and 256.

When using HTTP/2, this option sets the individual weight for this particular
stream used by the easy \fIhandle\fP. Setting and using weights only makes
sense and is only usable when doing multiple streams over the same
connections, which thus implies that you use \fICURLMOPT_PIPELINING(3)\fP.

This option can be set during transfer and causes the updated weight info get
sent to the server the next time an HTTP/2 frame is sent to the server.

See section 5.3 of RFC 7540 for protocol details.

Streams with the same parent should be allocated resources proportionally
based on their weight. So if you have two streams going, stream A with weight
16 and stream B with weight 32, stream B gets two thirds (32/48) of the
available bandwidth (assuming the server can send off the data equally for
both streams).
.SH DEFAULT
If nothing is set, the HTTP/2 protocol itself uses its own default which is
16.
.SH PROTOCOLS
HTTP/2
.SH EXAMPLE
.nf
int main(void)
{
  CURL *curl = curl_easy_init();
  CURL *curl2 = curl_easy_init(); /* a second handle */
  if(curl) {
    curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/one");
    curl_easy_setopt(curl, CURLOPT_STREAM_WEIGHT, 10L);

    /* the second has twice the weight */
    curl_easy_setopt(curl2, CURLOPT_URL, "https://example.com/two");
    curl_easy_setopt(curl2, CURLOPT_STREAM_WEIGHT, 20L);

    /* then add both to a multi handle and transfer them! */
  }
}
.fi
.SH AVAILABILITY
Added in 7.46.0
.SH RETURN VALUE
Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not.
.SH "SEE ALSO"
.BR CURLMOPT_PIPELINING (3),
.BR CURLOPT_PIPEWAIT (3),
.BR CURLOPT_STREAM_DEPENDS (3),
.BR CURLOPT_STREAM_DEPENDS_E (3)
